Nanoparticles as used in the present invention are particles made of a synthetic or natural polymer and having a diameter in the range of 1 to 1000 nm. It could be shown in the prior art that nanoparticles are suitable to bind (e. g. adsorb, absorb, encompass) natural or synthetic substances like drugs, medicaments, diagnostic agents, antisense oligonucleotides, proteins, plasmids etc.) and carry such substances to target organs in the human or animal body, like the brain, liver, kidneys etc. (WO 95/22963 and WO 98/56361). Particularly, it could be demonstrated that nanoparticles may be used for carrying medicaments for the treatment of cancers to a target organ including the brain. In other words: Medicaments which otherwise do not pass across the blood brain barrier (bbb) are enabled to do so by binding them to suitable nanoparticles (WO 00/74658).
In particular, it was found that nanoparticles made, by polymerization, of a monomer selected from the group consisting of methylmethacrylates, alkylcyano-acrylates, hydr-oxyethylmethacrylates, methacrylic acid, ethylene glycol dimethacrylate, acrylamide, N,N′-bismethylene acrylamide, 2-dimethylaminoethyl methacrylate, N,N-L-lysinediyltere-phthalate, polylactic acid, polylactic acid-polyglycolic acid-copolymers, polyanhydrates, poly-orthoesters, gelatin, albumin, desolvated macromolecules or carbohydrates, polystyrene, poly(vinylpyridine), polyacroleine and polyglutaraldehyde in the presence of a stabilizer allowing the passage of the blood brain barrier, said particles optionally being coated by a substance as Polysorbate® 80 (Polyoxyethylene (20) sorbitan monooleate=Tween® 80) or the like, may be used to carry cancer treatment drugs like doxorubicine to a specific target organ like the brain (by passing accross the blood brain barrier) while other organs are not affected by said drug.
The transfection of genes or DNA, respectively, into cells in vivo with microparticles is described in the U.S. Pat. No. 6,248,720. The microparticles consisting of bioadhesive polymers, which are defined as polymers having the capability to bind to mucosal epithelium under normal physiological conditions, are administered orally or by inhalation and contain genes under the control of a promoter. The gene delivered may then be used for gene-therapeutic methods to be effected within the cell. This approach, however, could not be transformed into a practically useful method for transfecting genes into all kinds of cells, particularly due to the fact that the gene or DNA, respectively, transported by the microparticle could not pass across physiological barriers like the blood brain barrier. In accordance therewith, the above U.S. patent teaches only the unspecific gene therapy for the treatment of epithelial cells, gut-associated lymphatic cells, spleen cells or liver cells.
On a worldwide basis, tumors of the brain belong to the widespread tumors observed for young people. In the United States, 180,000 new cases of different brain tumors are found to occur, in particular tumors of the heterogeneous group of malign gliomas, which covers anaplastic astrocytomes, glioblastomes and, especially, the highly malign glioblastoma multiforme. The fact that preparations for pharmacologically suppressing the formation of recidives are not yet available, results into a high mortality of young people affected by such tumors. It is, hence, highly desired to find methods of successful treatment of such tumors in order to obtain an improvement of the rate of a successful treatment.
Malign gliomas and glioblastomes in humans are, in most cases, treated by surgical removal of the tumor tissue, followed by chemotherapy and/or irradiation. In many of the cases, the chemotherapy treatment is not satisfactory, since there are two barriers to overcome for cytostatic agents in the treatment step before having full effect, i. e. the blood brain barrier and a frequently occurring intrinsic chemoresistance of the blood brain barrier and of the tumor. Hence, it is essential in the course of the pharmacological treatment of brain tumors of the above kind to develop strategies for a transport of said chemotherapeutic agents across the blood brain barrier in vivo. Among the known methods are methods of opening the brain (invasive treatment) for opening the blood brain barrier, methods of modifying the pharmacological agent, whereby the modification enables the agent to pass across the blood brain barrier, and methods of using chimeric peptides for targeting small pharmacologically effective molecules to specific sites within the brain.
In the above-referenced WO publications, inter alia, proposals were made for drug delivery systems allowing the targeting of drugs including anti-cancer drugs to specific organs in the human or animal body, and in particular to the brain whereby drugs which are known not to pass the blood brain barrier could be transported into the brain in order to treat brain cancers. Particularly, after coating nanoparticles loaded with an analgetic drug (e. g. the hexapeptide-encephaline, dalargine) or with an anti-cancer drug (e. g. doxorubicine) with Polysorbate® 80 and administering such pharmacological nanoparticle-containing compositions in a suitable vehicle to the human or animal body, an increased concentration of said drugs in the brain could be determined, compared to the case of an administration of said drugs alone, but without the nanoparticle drug delivery system.
Most approaches to deliver genes to cells make use of viruses or viral vectors into which genes or plasmids are inserted. Cells or tissue of the body is then exposed to the virus or viral vector containing the gene or plasmid. The virus then infects or enters into the cell and liberates the gene or plasmid into the interior of the cell. Ideally, the gene is then transcribed within the cell, and the resulting transcription products are biologically active. However, the approach using viruses or viral vectors has numerous problems, one of them being that viral vectors may produce toxic side effects. In addition, they provoke an immune response which is undesirable. Furthermore, a continuously expressing gene can be “switched off” by the cellular response and, thus, become inactive in a process of tolerance. Finally, viral vectors, due to their unspecific distribution within the body, do not allow a targeting of genes/DNA to specific sites within the body, particularly no targeting to areas protected by natural barriers as the blood brain barrier.